/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.cf.code;

import com.android.dx.util.Hex;
import com.android.dx.util.IntList;
import com.android.dx.util.LabeledItem;

/**
 * Representation of a basic block in a bytecode array.
 */
public final class ByteBlock implements LabeledItem {

	/** {@code >= 0;} label for this block */
	private final int label;

	/** {@code >= 0;} bytecode offset (inclusive) of the start of the block */
	private final int start;

	/** {@code > start;} bytecode offset (exclusive) of the end of the block */
	private final int end;

	/** {@code non-null;} list of successors that this block may branch to */
	private final IntList successors;

	/** {@code non-null;} list of exceptions caught and their handler targets */
	private final ByteCatchList catches;

	/**
	 * Constructs an instance.
	 * 
	 * @param label
	 *            {@code >= 0;} target label for this block
	 * @param start
	 *            {@code >= 0;} bytecode offset (inclusive) of the start of the
	 *            block
	 * @param end
	 *            {@code > start;} bytecode offset (exclusive) of the end of the
	 *            block
	 * @param successors
	 *            {@code non-null;} list of successors that this block may
	 *            branch to
	 * @param catches
	 *            {@code non-null;} list of exceptions caught and their handler
	 *            targets
	 */
	public ByteBlock(int label, int start, int end, IntList successors,
			ByteCatchList catches) {
		if (label < 0) {
			throw new IllegalArgumentException("label < 0");
		}

		if (start < 0) {
			throw new IllegalArgumentException("start < 0");
		}

		if (end <= start) {
			throw new IllegalArgumentException("end <= start");
		}

		if (successors == null) {
			throw new NullPointerException("targets == null");
		}

		int sz = successors.size();
		for (int i = 0; i < sz; i++) {
			if (successors.get(i) < 0) {
				throw new IllegalArgumentException("successors[" + i + "] == "
						+ successors.get(i));
			}
		}

		if (catches == null) {
			throw new NullPointerException("catches == null");
		}

		this.label = label;
		this.start = start;
		this.end = end;
		this.successors = successors;
		this.catches = catches;
	}

	/** {@inheritDoc} */
	@Override
	public String toString() {
		return '{' + Hex.u2(label) + ": " + Hex.u2(start) + ".." + Hex.u2(end)
				+ '}';
	}

	/**
	 * Gets the label of this block.
	 * 
	 * @return {@code >= 0;} the label
	 */
	public int getLabel() {
		return label;
	}

	/**
	 * Gets the bytecode offset (inclusive) of the start of this block.
	 * 
	 * @return {@code >= 0;} the start offset
	 */
	public int getStart() {
		return start;
	}

	/**
	 * Gets the bytecode offset (exclusive) of the end of this block.
	 * 
	 * @return {@code > getStart();} the end offset
	 */
	public int getEnd() {
		return end;
	}

	/**
	 * Gets the list of successors that this block may branch to
	 * non-exceptionally.
	 * 
	 * @return {@code non-null;} the successor list
	 */
	public IntList getSuccessors() {
		return successors;
	}

	/**
	 * Gets the list of exceptions caught and their handler targets.
	 * 
	 * @return {@code non-null;} the catch list
	 */
	public ByteCatchList getCatches() {
		return catches;
	}
}
